In the face of harsh external environment, ordinary wood can not resist mold, rain and other erosion, easily perishable, and the use of preservatives poison wood after preserving wood, you can prevent rotten wood rotten wood, in a vacuum, Antiseptic agents invade the wood tissue into cells, tightly mixed with their fibrous tissue, and the medicament will not be released. As a result of the pressure process dipped in pharmaceuticals, the wood will be slightly green with the color of the chemical, and uneven color, color difference is dull, with the loss of chemicals, but also easy to gray, black, and generally did not take two Dry, the wood itself, the high water content, so prone to deformation, cracking problems.